The objective of this contract is to conduct a third series of studies over a nine year period designed to 1) conduct the first longitudinal study of age effects on cardiavescular function in the BLSA population by repeating gated blood pool scan examinations during rest and exercise; 2) determine the effect of ischemic heart disease on cardiac function in the BLSA participants and how age alters that effect; 3) assess the effect of physical conditioning status and body composition on the central and peripheral cardiovascular response to exercise in the BLSA population; 4) perform exercise tomographic thallium scintigraphy so as to insurue the absence of subclinical disease in the BLSA participants chosen for the above studies of cardiovascular function; and 5) conduct a longitudinal assessment of age related incidence and prognostic significance of a change in myocadial flow distribution over an 8-10 year period.